Astronomers have identified Gliese 3378b, a rocky super-Earth orbiting within the habitable planet of a nearby red dwarf star. Located just 25 light-years away, it has become a notable addition to the growing list of nearby worlds that may warrant closer study.
The newly characterized exoplanet has a mass about 2.3 times that of Earth and completes one orbit around its host star every 21.45 days. While its location within the habitable zone makes it an appealing object for research, scientists say one key question has yet to be answered: whether the celestial body has managed to retain an atmosphere.
This super-Earth, also cataloged as GJ 3378, LHS 1805, and TIC 322347050, is a red dwarf located in the northern constellation of Camelopardalis. Research published in The Astrophysical Journalreports that the star lies approximately 25 light-years from Earth. Its newly characterized planet receives about 90% of the radiation that Earth receives from the Sun, placing it within the star’s habitable zone, where liquid water could exist on a planet’s surface under suitable atmospheric conditions.
Red Dwarfs Remain A Key Focus For Planet Hunters
The discovery also draws attention to the importance of the worlds orbiting red dwarfs, the most common type of star in the Milky Way. Dr. Michael Endl, an astronomer at the University of Texas at Austin, said that roughly 70% of the stars in our galaxy are red dwarfs, making them representative of the environments where planets commonly form.
Understanding the population of planets around these stars, he explained, is an important step toward understanding planetary systems across the galaxy.
Although a distance of 25 light-years may seem enormous, Dr. Paul Robertson of the University of California, Irvine placed it in perspective. He noted that the Milky Way spans about 100,000 light-years, making Gliese 3378 a close neighbor on a galactic scale.
A Planet in The Right Place
The research team used two ground-based instruments to study the planetary system. The observations combined data from theHabitable-zone Planet Finderon theHobby-Eberly Telescopeat McDonald Observatory in Texas with measurements from the NEID Spectrometer on the WIYN Telescope at Kitt Peak National Observatory in Arizona.
The study determined that Gliese 3378b has a mass approximately 2.3 times that of Earth and circles its host star every 21.45 days. Robertson said that:
“This super-Earth gets about 90% of the radiation from its host star as Earth gets from the Sun, so it’s right in the sweet spot.”
That amount of incoming radiation positions the planet inside the habitable zone, where temperatures may allow liquid water if the necessary atmospheric conditions are present.
The Atmosphere Remains a Mystery
Despite its favorable orbit, the presence of an atmosphere remains uncertain.The paper describes Gliese 3378b as lying near the cosmic shoreline, a region where radiation from a host star may gradually strip away a planet’s atmosphere. The researchers pointed to Marsas an example from our own Solar System.
Astronomers believe the planet may once have possessed an atmosphere more similar to Earth’s before solar radiation removed much of it over time. Robertson illustrated the importance of an atmosphere by comparing Earth to an apple.
“If you scale the Earth down to the size of an apple, its atmosphere would be about as thick as the skin of the apple,” he said. “That’s just enough to maintain the kinds of surface pressures where you can have liquid water.”
The discovery adds another candidate to the list of exoplanets that may prove hospitable to life. Gogod James, a student at the University of California, Irvine, said that confirming the presence of a suitable atmosphere would justify further research aimed at detecting biosignatures, liquid water, or other signs of life that depend on both an atmosphere and the amount of heating received from the host star.
